Today, the notion of the melting pot can no longer explain the process of assimilation in American society. The current cultural scene is comprised of a mainstream group and a large number of subcultural enclaves. The coexistence of these groups leads to tensions between the mainstream culture and the various subcultures, in this case, the immigrant ones. Transformation of the ethnic enclaves occurs over generations of interchange with the mainstream environment and results in specialized communities that are a hybrid of the immigrant's culture and the prevailing American one. This thesis explores the dialectical relationship between culture and city form by analyzing the evolution of the Islamic community of Dearborn, Michigan, which has the densest concentration of Arab Muslims in America. It traces the original Southend community, which has an irregular, agglomerate city form, to the later developed Eastend community, which has a grid-like city form. This thesis then examines a vision to design a new Islamic community at a proposed site in Plymouth, Michigan. How and to what extent ethnicity is expressed in the physical form of all three communities is examined. Issues of self-image and representation are also explored. The proposed Plymouth project exemplifies three architectural and urban planning trends: the building of state mosques in the Islamic world, the development of American suburbs, and the creation of subcultural enclaves by design. If it is built, the new Islamic community in Plymouth will be a compromise between the maintenance of self-identity and integrity of the immigrant subgroup and total assimilation and integration with the mainstream. . The architectural message sent by these designed ethnic enclaves to the mainstream culture represents new attitudes of the enclave members about their own identity and role in American society. The melting pot model of assimilation is being replaced with a model of distinct but open subcultures. The result will be a culturally pluralistic urban form, where group interchange diffuses polarization and promotes understanding.